chapter 20&21 Flashcards
Describe the body of molluscs
- they are soft and most of them are covered with a calcium carbonate shell
How common are molluscs?
fairly common over 150,000 species
What is the basic body plan of molluscs?
1) single muscular foot
2) visceral mass = contains most of its internal organs and true coelom
3) mantle = covers the viscera and secrets shell
Are molluscs eumetozoans?
Yes
What body cavity is present in molluscs?
coelom
What is the visceral mass found in molluscs?
it contains most of their internal organs including the coelom
Describe the mantles of molluscs
It covers all of the viscera and secretes calcium carbonate to make the shell
What are three main classes of molluscs
1) gastropoda
2) bivalvia
3) cephalopoda
What are gastopodas? Where do they live? Describe their body? What of feeders are there? Give examples.
a class of molluscs that live in water and land
- they have a spiral shell (most)
- they are herbivores mostly, and scrape algae off with their radula
- eg. snails, slugs
What makes it possible for gastropods (molluscs) to eat?
their radula
Describe the bivalvias. Where do they live? Describe their body? What of feeders are there? Give an example
- a class of molluscs that live in water
- they have a shell with two halves
- and filter feeders (mostly)
- clam and mussels
Describe the cephalopodas. Where do they live? Describe their body? What of feeders are there? Give an example.
- they live in water. (aquatic and marine)
- food is modified into tentacles with suckers
- they are predators
- octopi, squid
What is modified in cephalopods?
foot is modified into tentacles with suckers
The animals in the phylum annelida are also called?
segmented worms
How long are phylum annelids?
1 mm - 3 mm
Are annelids aquatic or terrestrial?
both
Are segmented worms, scavengers, decomposer, free living or parasites?
scavengers and decomposers
Do molluscs have a body cavity? If so, what does this mean in terms of tissue layers? What body cavity is present?
Yes
- they are eumetozoans
- a true coelom
Describe the body of segmented worms.
They have many segments and some organs are repeated in each segment
What are the different classes of annelids
1) oligochaeta
2) polychaeta
3) hirudinea
Oligochaetes are also known as?
- terrestrial segmented worms
Give an example of an oligochaete.
earthworm
What do do oligochaetes have on each segments of their body?
a FEW bristles/stae
Oligochaetes are excellent ________. They are important in _________ and _________
- burrowers
- soil aeration
- decomposition of dead plant material
Where do polychaetes live?
in the ocean therefore they are marine animals
Are polychaetes (annelids) scavengers, predators, decomposers, filter-feeders?
some are predators, others are scavengers and filter feeders
Describe the body of polychaetes?
Each segment has many bristles/setae and 2 parapodia
Parapodias are present in polychaetes, what do they do?
they function for swimming, crawling, feeding, and as gills
Give an example of hirudineans.
leeches
where do hirudineans live?
wet places because they dry out very easily
What kind of feeders are hirudineans?
most are scavengers and carnivores (but only a few are blood sucking)
Describe the body of hirudineans?
- they are somewhat flattened
- they lack bristles/setea, and parapodia
- they have 2 suckers, one posterior and one anterior
How long are hirudineans?
1 - 30 cm long
How do hirudineans feed?
by making a slit with their blade-like jaw and releasing enzyme
Aside from secretion of enzyme, what do hirudineans secrete?
anesthetic
In blood sucking hirudineans, what do they release?
they release an anticoagulant called hirudin which is used for medical purposes
How many species of the phylum arthropods are alive up to this day?
9 - 100 million species
How many species of arthropods have been successfully named?
about 1 million
Are arthropods aquatic or terrestrial?
both
Describe the body of arthropods.
1) jointed appendages
2) segmented bodies
3) chitinous exoskeleton
How are jointed appendages in arthropods modified?
According to function
In terrestrial arthropods, what does the chitinous exoskeleton do?
slow down water loss
Describe the segmented body of arthropods.
Some are fused together
how many sub phylum exist in the phylum arthropods.
4
what are the different subphylum of arthropods?
1) hexapoda
2) myriapoda
3) cheliceriformes
4) crustacea
70% of the identified species in the subphylum hexapoda (arthropods) are?
insects
How many insect species are there?
30 million
What are the 3 main body parts of hexapods
1) head
2) thorax
3) abdomen
The head of hexapods have?
a single pair of antennae
The thorax of hexapods have?
3 pairs of walking legs
Describe the eyes of hexapods
Usually they have 2 compound eyes but sometimes SEVERAL simple eyes
Many hexapods have wings and fly. True or False
True
The life cycles of insects are usually described as being?
1) incomplete metamorphosis
2) complete metamorphosis
What is an incomplete metamorphosis of hexapods.
the egg hatches into a nymph (miniature of the adult) and grows larger until it’s adult size
What insect goes through an incomplete metamorphosis?
grasshopper
What is a complete metamorphosis insect life cycle?
a life cycle that facilitates complete body form changes
What insect(s) goes through a complete metamorphosis?
beetles, flies and butterflies
In terms complete metamorphosis insect life cycle, do the larva and adult eat the same thing?
no
What is the metamorphosing stage in a complete metamorphosis insect life cycle? Does the organism eat in this stage?
pupal stage
- no
In simple form, recite the complete metamorphosis insect life cycle
fertilized egg –> larval stage –> pupal stage —> mature adult
Describe the segmented bodies of myriapodas
all segments are identical EXCEPT for the anterior end
- they legs on nearly all segments
Are myriapodas terrestrial or aquatic?
terrestrial
Give an example(s) of myriapodas.
centipedes and millipedes
Differentiate centipedes and millipedes in terms of physical appearance and what type of feeders they are
centipedes = 1 pair of legs/segment and they are carnivores millipedes = 2 pairs of legs/segment and they are herbivores
are cheliceriformes terrestrial or aquatic?
mostly terrestrial
Give an example(s) of cheliceriformes.
spiders and scorpions
Describe the body of cheliceriformes
1) They have a cephalothorax = fused head and thorax)
2) abdomen
The cephalothorax of cheliceriformes contain?
4 pairs of walking legs and 8 simple eyes (mostly)
Does the cephalothorax of cheliceriformes have an antenna?
no
Describe the abdomen of cheliceriformes (arthropods)
some have poison to paralyze their prey
What do spiders have to paralyze their prey?
they have fangs
What do scorpions have to paralyze their prey?
they have a stinger on end of tail
Are crustaceans (arthropods) aquatic or terrestrial?
Almost all of them are aquatic
How big are crustaceans?
1 mm - 4 m
Give examples of crustaceans
- crabs
- shrimp
- lobster
- water fleas
What kind of feeders are crustaceans?
1) the microscopic ones eat algae therefore they are herbivores
2) the larger ones are predators/scavengers
Describe the segmented body of crustaceans
they are often all fused
- some have a cephalothorax and separate abdomen